Spin-Lattice Relaxation in Ruby

Abstract

Spin-lattice relaxation times for ruby of very low Cr concentration at low temperature are computed for the one-phonon Kronig—Van Vleck process, using the spin-lattice Hamiltonian derived by Van Vleck and taking the vibrational anisotropy of the crystal into account. The relaxation times are computed as functions of the angle between the applied magnetic field and the $c$ axis, temperature, and frequency. Reasonably good agreement with experimentally determined relaxation times is obtained.